Multipath Reliability

At the 2016 LpS Symposium in Bregenz, Austria, our friends from Chess Wise recalled a very interesting study on reliability of wireless systems. Professor Holger Hermanns of Saarland University have developed a wireless bike brake system with a fail rate of three times in a trillion attempts. Or 99.999999999997 percent.

The secret? Multiple senders attached to the bicycle repeatedly send the same signal.

Multi-path delivery becomes the secret sauce of high reliability low power mesh networks and is especially applicable to lighting systems. The beauty of multi-path delivery is that it is an ideal (if not the only one) method of controlling a large group of devices (such as a hotel lobby with 500 lights). The level of reliability achieved with multi-path essentially removes the need of acknowledgements being sent back to the sender.

And the math is simple:

• 500 lights, all controlled as a group
• Single path delivery with acknowledgements: 1000 messages + retry logic
• Multi-path delivery to achieve the same reliability: 10 messages

This means a multi-path system may be 100x more efficient and still way simpler to build / commission / maintain. No routes to set up  and maintain. No popcorn effect. Wire-like reliability and performance.